Cross Sections for the Alkali-Metal-Halogen Molecule Reactions: Na, K, Rb, and Cs with I2

Abstract

The reaction cross sections of alkali‐metal atoms with I₂ molecules were obtained by direct measurements of alkali‐atom decay rates. The alkali atoms were produced in the presence of a known amount of I₂ molecules, by photodissociating the alkali iodide salt with a short pulse of uv light. As the alkali atoms reacted with the I₂ molecules their decay was monitored by observing the transmission of alkali atom resonance light through the vapor. The cross sections were computed from the decay rates. They are: Na: 97 Ų; K: 127 Ų; Rb: 167 Ų; Cs: 195 Ų. These results are in good agreement with the cross sections computed from a modified orbiting theory.